Element for electromagnetic shielding and method for manufacturing thereof

ABSTRACT

A method for manufacturing an element ( 5 ) for electromagnetic shielding. The method is characterised by the steps of arranging, along a curve corresponding to the extension of the completed element ( 5 ), a viscous material ( 7 ) in the form of a bead ( 6 ), and orienting the particles ( 9 ) in the material ( 7 ) by applying a magnetic field ( 10 ) across said bead  86 ). The material ( 7 ) carries particles ( 9 ) with substantial electrical conductivity and also ferromagnetic and/or ferrimagnetic properties. The present invention also concerns a corresponding element for electromagnetic shielding, a device for electromagnetic shielding comprising such an element, use of such an element in a mobile phone and at a base station, and also a mobile phone and a base station comprising such an element.

FIELD OF THE INVENTION

[0001] The present invention relates to an element for electromagneticshielding, a method for manufacturing thereof and a device comprisingsuch an element. More specifically, the invention concerns such anelement for electromagnetic shielding, comprising an elastic materialwhich carries particles with substantial electrical conductivity.

BACKGROUND ART

[0002] For expedient function, electronic-equipment must, usually beshielded from electromagnetic radiation. The equipment may also comprisecomponents which themselves generate electromagnetic radiation that mustbe shielded.

[0003] To provide such shielding, the electronic equipment, or itscomponents, is normally enclosed in casings with electricalconductivity, which consequently act as a Faraday cage.

[0004] To allow access to the electronic equipment or its components,these casings are usually made to be opened, in which case elasticelements of the type described by way of introduction are used to ensurethe necessary shielding.

[0005] Such an element is known from, for example, GB 2049718. Theelement described comprises an elastic, electrically non-conductivematerial which carries electrically conductive flakes. The flakes areoriented to increase the conductivity of the element in a certaindirection. To achieve this orientation, the material, when stillviscous, is subjected to a shearing process, which can be effected byextrusion. Subsequently, the material is allowed to cure, after whichthe material is sliced in a direction which is preferably perpendicularto the direction of extrusion. The completed element is finally punchedfrom the slices of material. Although the thus manufactured elements forelectromagnetic shielding have an advantageous conductivity in a desireddirection, they are difficult to manufacture and besides it is difficultto provide more complicated designs of the elements.

[0006] Moreover, a casing with an elastic element of the type describedby way of introduction is known from, for example, U.S. Pat. No.5,882,729.

[0007] The element described in the above publication is manufactured bydispensing a viscous material carrying particles with substantialelectrical conductivity on a housing. The viscous material is dispensedin the form of a bead of the required extension, after which thematerial is treated to assume an elastic, non-viscous state. The elementensures good electric contact between the housing and a cover when thisis closed and caused to abut against the element.

[0008] A problem with elements of this type is that the particles thatprovide the electrical conductivity of the element are relativelyexpensive. It would therefore be desirable to reduce the amount ofparticles which is included in the element.

[0009] Furthermore, for dispensing to be possible, the material musthave a relatively low viscosity. As a result, the dispensed bead willhave a shape corresponding to a lying D.

[0010] A thus designed element requires a relatively high compressionforce to achieve the necessary electric contact between, for instance, ahousing and a cover.

[0011] In many fields, it is required that the electronic equipment bemade increasingly smaller. For instance, there is an ongoing developmenttowards manufacture of smaller, thinner and lighter mobile phones.Unnecessarily high compression forces may in this context causedeformation of the casing of the mobile phone.

[0012] Also in shielding covers for base stations for mobile telephonythere is a need for lowered compression forces in shielding elements,since the now prevailing relatively high compression forces requireexpensive stiffeners and/or great wall thicknesses.

[0013] There is thus a need for elements that require lower compressionforces. The solution suggested in U.S. Pat. No. 5,882,729 is dispensingof a plurality of beads, thereby building a vertically tapering element.It will be appreciated that this is a complicated and time-consumingprocess which has a detrimental effect on the cost of manufacture of theelement.

[0014] A further method of making thus tapering elements is injectionmoulding, but this is not a practically applicable method forsurface-sensitive or large components.

[0015] Finally it is known from U.S. Pat. No. 4,778,635 to make amaterial with anisotropic electrical conductivity by subjecting aviscous material, which carries electrically conductive particles, to aspatially varying magnetic field while at the same time the materialcures. More specifically, the varying magnetic field affects theparticles so that they are concentrated in beads whose positions arelocked as the material cures.

SUMMARY OF THE INVENTION

[0016] In view of the above, an object of the present invention is toprovide an improved element for electromagnetic shielding and acorresponding method for manufacturing thereof.

[0017] Another object is to provide an improved device forelectromagnetic shielding comprising such an element.

[0018] The element should preferably have good electrical conductivityin spite of a reduced particle content.

[0019] The element should also preferably require a reduced compressionforce.

[0020] To achieve these objects, and also other objects that are evidentfrom the following description, a method is provided according to thepresent invention for manufacturing an element for electromagneticshielding having the features stated in claims 1 and 16, respectively, adevice for electromagnetic shielding having the features stated in claim17, an element for electromagnetic shielding having the features statedin claim 18, use of an element having the features stated in claims 26and 28, respectively, a mobile phone having the features stated in claim27, and a base station having the features stated in claim 29. Preferredembodiments of the inventive method are evident from claims 2-15 whichare dependent from claim 1, and preferred embodiments of the element areevident from claims 19-25.

[0021] More specifically, according to the present invention a method isprovided for manufacturing an element for electromagnetic shielding,which method is characterised by the steps of arranging a viscousmaterial in the form of a longitudinally extended bead, the materialcarrying particles with substantial electrical conductivity andferromagnetic and/or ferrimagnetic properties, and orienting theparticles in the material by applying a magnetic field across said bead.

[0022] By the term viscous material which is used above and in thefollowing is meant a sticky, viscous material. Such a material can, forinstance at a shear rate of 10⁻¹ s, have a viscosity in the range 30-300Pas.

[0023] This results in an improved method for manufacturing an elementfor electromagnetic shielding. Owing to the fact that the particles areoriented by applying a magnetic field, the electrical conductivity ofthe element is improved. More specifically, the particles will bearranged in rows along the field lines of the magnetic field. It willthus be possible to provide a given conductivity with a reduced amountof particles. Since the cost of said particles constitutes a main partof the total cost of material for the element, this reduced need forparticles results in a considerable saving in costs. An element with areduced particle content requires also a lower compression force. Thereason is that the particles act to reinforce the material of theelement. Thus, a reduced particle content results in reducedreinforcement.

[0024] The inventive method comprises advantageously also the step oftreating the bead in such a manner that the material assumes an elastic,non-viscous state, whereby the particles are fixed with maintainedorientation. Advantageously the material is selected from the groupconsisting of silicone rubber, polyurethane and TPE. If the material issilicone rubber, the material is treated by a curing process, whereby itassumes an elastic, nonviscous state while the particles are fixed withmaintained orientation.

[0025] According to a preferred embodiment of the inventive method, themagnetic field applied across the bead is given such a strength and/orduration that the particles, during their orientation in the samedirection as the magnetic field, affect the geometry of the bead. Themagnetic field is advantageously directed so that the particles, duringtheir orientation, affect the material of the bead in such a manner thatthe bead assumes a geometry tapering from a base towards an apex. A thusdesigned element requires a reduced compression force.

[0026] According to another preferred embodiment, the magnetic fieldapplied across the bead is given such a strength and/or duration that aconcentration of particles is provided in the surface layer of the bead.In some cases, it is in fact in the surface of the element that the needfor substantial electrical conductivity is at its greatest. The magneticfield treatment thus makes it possible to ensure that the requisiteconductivity is provided in said surface layer while the particlecontent of the other parts of the material can be brought to a minimum.This means that the particle need may be further reduced, which has apositive effect on the manufacturing cost as well as the requiredcompression force.

[0027] According to yet another preferred embodiment of the presentinvention, said bead is made by a dispensing process. Alternatively, thebead can be made by a screen-printing process.

[0028] The material is advantageously arranged in the form of a bead ona substrate and is arranged for adhesion thereto. The magnetic field isadvantageously directed so as to act perpendicular to and in a directionaway from the surface of the substrate, on which surface the material isarranged.

[0029] The magnetic field applied across the bead preferably has a fluxdensity in the range 0.01-1 Tesla.

[0030] The particles are preferably formed so as to contain aferromagnetic material such as iron, nickel, cobalt, or an alloycontaining one or more of said ferromagnetic materials.

[0031] The particles are preferably also formed with an outer layer of amaterial having substantial electrical conductivity.

[0032] The outer layer preferably forms also an oxidation inhibitor fora ferro- and/or ferromagnetic material arranged inside the outer layer.

[0033] Furthermore, according to the present invention a method isprovided for manufacturing an electromagnetic shielding element, whichmethod is characterised by the steps of arranging, by a dispensingprocess, a bead of a viscous material, such as silicone rubber, andparticles carried therein and having substantial electrical conductivityand ferro- and/or ferromagnetic properties on a substrate, orienting theparticles carried by the material by applying a magnetic field acrossthe bead, the magnetic field being directed so as to act perpendicularto the substrate in a direction away from the surface of the substrate,on which surface said bead is arranged, and treating the material so asto assume an elastic, non-viscous state.

[0034] Further a device for electromagnetic shielding is provided,comprising an element made according to the method as described above.

[0035] According to the invention, also an element for electromagneticshielding is provided, comprising an elastic material which carriesparticles with substantially electrical conductivity, which element ischaracterised in that the particles are oriented in the material.

[0036] Thus, an element is provided which has extremely good electricalconductivity in relation to particle content. To achieve a givenconductivity, it will thus be possible to reduce the particle content,which has a positive effect on the manufacturing cost. Also the forcerequired for compressing the material is reduced.

[0037] According to a preferred embodiment of the element, saidparticles are oriented so that a concentration of particles is presentin a surface layer of the material.

[0038] The material included in the element preferably consists ofsilicone rubber, polyurethane or TPE.

[0039] According to another preferred embodiment, the particles haveferro- and/or ferrimagnetic properties. This makes it possible toachieve said orientation of the particles by applying a magnetic fieldacross the element when its material is present in a viscous state. Theparticles advantageously contain nickel, iron, cobalt, or an alloycontaining one or more of these.

[0040] According to one more preferred embodiment, the particles have anouter oxidation-inhibiting layer with substantial electricalconductivity, the oxidation-inhibiting layer preferably containingsilver.

[0041] According to another embodiment, the element has a shape taperingfrom a base towards an apex. This reduces the force required forcompressing the element.

[0042] According to one more embodiment, the elastic material alsocarries particles with substantial electrical conductivity and withoutferro- or ferrimagnetic properties.

[0043] According to the present invention, there are also provided useof an element as described above for electromagnetic shielding in amobile phone, and a mobile phone containing such an element.

[0044] Finally, according to the present invention, there are provideduse of an element as described above for electromagnetic shielding at abase station, and also a base station containing such an element.

[0045] The present invention will now be described by way of example andwith reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0046]FIG. 1 is a perspective view of an inventive shielding device withan element for electromagnetic shielding.

[0047]FIG. 2 is a part-sectional perspective view of an element forelectromagnetic shielding in a state before its particles have beenoriented according to the present invention.

[0048]FIG. 3 is a schematic view of the process for orienting theparticles in the element shown in FIG. 2.

[0049]FIG. 4 is a cross-sectional view of an alternative embodiment ofan inventive element for electromagnetic shielding.

[0050]FIG. 5 is a cross-sectional view of another alternative embodimentof an inventive element for electromagnetic shielding.

DESCRIPTION OF THE EMBODIMENTS

[0051]FIG. 1, to which-reference is made, illustrates an inventivedevice 1 for electromagnetic shielding.

[0052] The device 1 comprises a casing 2 with an opening 3 and a flange4 surrounding the opening 3. The casing 2 has substantial electricalconductivity and can thus be made of metal or metallised plastic. Thecasing 2 may also comprise a body without substantial conductivity, inwhich case a layer of substantial conductivity is applied to the innerand/or outer surface of the casing 2.

[0053] The device 1 further has an element 5, which is applied to thecircumferential flange 4 and has a shape tapering from a base towards anapex. The tapering shape means that the force required for compressingthe element 5, and thus providing good electric contact, is reduced.

[0054] The element 5 is made of an elastic material which carriesparticles with substantial electrical conductivity. According to apreferred embodiment, the elastic material consists of silicone rubberwhile the particles consist of nickel with an outer silver layer. Theelement 5 and the method for manufacturing thereof will be described inmore detail below.

[0055] The device 1 for electromagnetic shielding can be used forshielding electronic equipment (not shown), such as a base station formobile telephony. The equipment is arranged in the casing 2 after whichit is closed with a suitably designed cover (not shown). The element 5ensures that good electric contact is provided between the casing 2 andthe cover.

[0056] The inventive device 1 can also be used for shielding ofelectronics in electronic equipment such as one or more components on aprinted circuit board (not shown). The device 1 forms a casing 2 whichis applied over the group of components, the element 5 ensuring thatgood electric contact between the casing 2 and the printed circuit boardis provided.

[0057] The size of the inventive device 1 is of course adapted to thetechnical field in question.

[0058] It will be appreciated that the device 1 can also be configuredin other ways. For example, it is possible to make the device 1 in theform of a frame which on opposite sides supports an element 5 forelectromagnetic shielding, which elements are in electric contact witheach other. The frame may then be used, for instance, as a spacer in amobile phone, such as between two printed circuit boards or between afront and a back of the cover of the mobile phone.

[0059]FIG. 2, to which reference is now made, illustrates the appearanceof an inventive element 5 during the manufacturing process.

[0060] A bead 6 of a viscous material 7, such as silicone rubber, isapplied to a substrate 8 by a dispensing process, in which the material7 is ejected through a needle nozzle (not shown) which is advanced overthe substrate 8 along a curve corresponding to the extension of thecompleted element 5. To ensure good adhesion between the bead ofmaterial 6 and the substrate 8, a primer can be applied to the substrate8 before dispensing of the bead 6.

[0061] For such a dispensing process to be allowed, the material 7 musthave a relatively high viscosity, whereby the material 7, owing togravity, will assume the shape of a lying D. Preferably the material hasa viscosity in the range 30-300 Pas at a shear rate of 10⁻¹ s whenmeasuring in a rheometer Physica-Rheolab MC1 with a plate/platemeasuring system.

[0062] The material 7 carries particles 9 with substantial electricalconductivity and ferro- and/or ferrimagnetic properties.

[0063] According to the preferred embodiment, the particles 9 consist ofnickel with an outer silver layer. Nickel is ferromagnetic while thesilver layer acts as an oxidation inhibitor for the nickel. The silveralso promotes the improvement of the electrical conductivity of theparticles 9.

[0064] The particles are preferably spherical, round, needle-shaped orlump-shaped, such as irregular granules.

[0065]FIG. 3, to which reference is now also made, illustrates the nextstep for manufacturing the inventive element 5.

[0066] The magnetic field 10 is applied across the material 7 arrangedin the form of a bead 6. The magnetic field 10 is directed so as to actperpendicular to the substrate 8 away from the surface 11 on which thematerial 7 is arranged. The Figure illustrates how the magnetic field 10is applied by means of an electromagnet 12. However, it will beappreciated that the magnetic field 10 can be provided in other ways.

[0067] Owing to the ferromagnetic properties of the particles 9, theparticles will be affected by the magnetic field 10 and orientthemselves in the same direction as the magnetic field 10. Morespecifically, the particles 9 will be oriented in rows extended alongthe field lines of the magnetic field 10. The orientation of theparticles in rows is clearly to be seen from the enlargement of a detailin FIG. 2.

[0068] The orientation of the particles is facilitated by theiradvantageous shapes stated above. In the FIGURES, the particles areneedle-shaped in order to clearly illustrate their orientation caused bythe magnetic field.

[0069] The orientation of the particles 9 promotes improvement of theelectrical conductivity of the element 5. Owing to said magnetic fieldtreatment, it is thus possible to reduce the amount of particles 9 forproviding a given conductivity in the element 5. This means aconsiderable saving in costs. The reduced amount of particles 9 alsoimplies that the force required for compressing the element 5 is reducedsince the particles 9 cause a reinforcement of the material 7. It goeswithout saying that a reduced amount of particles 9 will result in asmaller reinforcement.

[0070] By a suitable adaptation of the flux density of the magneticfield 10 it will be possible to cause the particles 9, during theirorientation, to affect the material 7 of the bead 6 in such a mannerthat the bead 6 changes its geometry. It is evident from FIG. 3 how thebead 6 has assumed an essentially triangular geometry with a shapetapering from a base 13 towards an apex 14. Thus the magnetic field 10affects the particles 9 so that the particles during their orientationin turn act on the material 7 and extend it in the vertical direction.

[0071] The magnetic field has a field strength preferably in the range0.01-1 Tesla.

[0072] Subsequently the material 7 is treated in a suitable manner tomake it assume an elastic, non-viscous state, whereby the particles 9are fixed with maintained orientation. If the material 7 consists ofsilicone rubber, this is subjected to a conventional curing process.

[0073] In a practical experiment, a bead 6 of silicone rubber wasdispensed on a substrate 8. The silicone rubber carried particles 9 inthe form of nickel with an outer silver layer. The particles had adiameter in the range 10-100 μm, average diameter 40 μm. The bead 6assumed essentially the shape of a lying D, width 1.3 mm and height 0.8mm. Then a magnetic field 10 with a magnetic flux density of 0.05 Teslawas applied across the bead 6 for 15 s in the manner as described above.The bead 6 thereby assumed a triangular shape with a height of 1.3 mm.

[0074] According to the present invention, an element 5 forelectromagnetic shielding and also a method for manufacturing thereofare provided. The element 5 comprises an elastic material 7 whichcarries oriented particles 9 with substantial electrical conductivity.Owing to the orientation of the particles 9, the element 5 can be madeto have a given conductivity in spite of a reduced particle content. Asa result, the manufacturing cost for the element 5 is lowered while atthe same time the necessary compression force can be reduced. Saidorientation is provided according to the present invention by applying amagnetic field 10 across a bead of the material 7 when in a viscousstate. In connection with the orientation of the particles 9 it is alsopossible to affect the geometry of the bead 6.

[0075] According to a preferred embodiment of the inventive method, thebead of material can be arranged directly on a substrate and be arrangedfor adhesion thereto. The substrate may consist of a flange 4 of thecasing shown in FIG. 1. However, other types of substrate areconceivable, such as a frame structure which is intended to be arrangedbetween two electrically conductive structures in the form of printedcircuit boards.

[0076] According to another embodiment (not shown), also particles withsubstantial electrical conductivity are carried by the material of theelement. These electrically conductive particles help to electricallyconnect the particles with electrical conductivity as well as ferro-and/or ferrimagnetic properties when these are arranged in rows alongthe field lines of the magnetic field applied across the bead. Thisimproves the electrical conductivity of the element still more.

[0077] The present invention is extremely useful in the mobile phoneindustry. There is a strong downward pressure on prices of mobile phonesand therefore all savings in cost are of benefit to the manufacturers.Besides, the fact that the required compression force of the element 5can be reduced means that the element 5 itself does not constitute a barto designing smaller, lighter and thinner mobile phones.

[0078] The present invention is also very useful in shielding covers forbase stations for mobile telephony. The reduced compression force of theinventive shielding element renders it possible to make the shieldingcover with a reduced wall thickness and/or without stiffeners.

[0079] It will be appreciated that the present invention is notrestricted to the embodiments described above.

[0080] For instance, it is conceivable to adjust the magnetic field 10so that a concentration of particles 9 is provided in the surface layer15 of the element 5, as shown in FIG. 4. The magnetic field 10 isadjusted in terms of strength and duration, whereby a great amount ofthe particles 9 is “extracted” from the material 7 and concentrated inits surface layer 15. A thus manufactured element 5 has extremely goodelectrical conductivity in the surface layer 15. This enables a furtherreduction of the amount of particles 9 in the material 7.

[0081] It is also conceivable to adjust the magnetic field 10 so thatmerely an orientation of the particles 9 is provided. The magnetic field10 is given a relatively small strength, whereby the particles 9 duringtheir orientation are not capable of affecting the geometry of thebead,-which is shown in FIG. 5.

[0082] Nor does the elastic material have to be arranged in the form ofa bead by a dispensing process. For example, it is possible to providethis bead by a screen-printing process.

[0083] It will also be appreciated that the elastic material included inthe element need not necessarily consist of a silicone rubber. Thus itis also possible to manufacture the inventive element from other elasticmaterials, such as polyurethane, TPE or the like.

[0084] The element 5 can further be given a complex geometricconfiguration. To achieve this, it is possible, for instance, todispense the particle-carrying material on a non-planar substrate, i.e.a substrate extending in three dimensions.

[0085] Finally, it will also be appreciated that the particles can bedesigned in a way other than that described above. The particlesadvantageously contain a material with ferromagnetic properties.Non-limiting examples of such materials are iron, nickel, cobalt, andalloys containing one or more of these materials. The particles may alsocontain materials with ferrimagnetic properties, in which case theparticles preferably also contain an outer layer with substantialelectrical conductivity since ferrimagnetic materials normally havelower electrical conductivity. As described above, however, alsoparticles containing ferromagnetic material may have such an outer layerwith substantial electrical conductivity. This may be required in thecases when the ferromagnetic material has a tendency to oxidation whichdeteriorates the electrical conductivity of the material.

[0086] Several modifications and variations are thus conceivable, andtherefore the scope of the present invention is exclusively defined bythe appended claims.

1. A method for manufacturing an element (5) for electromagneticshielding, characterised by the steps of arranging, along a curvecorresponding to the extension of the completed element (5), a viscousmaterial (7) in the form of a bead (6), the material (7) carryingparticles (9) with substantial electrical conductivity and ferromagneticand/or ferrimagnetic properties, and orienting the particles (9) in thematerial (7) by applying a magnetic field (10) across said bead (6). 2.A method as claimed in claim 1, wherein the step of orienting theparticles (9) is followed by the step of treating the bead (6) in such amanner that the material (7) assumes an elastic, non-viscous state,whereby, the particles (9) are fixed with maintained orientation.
 3. Amethod as claimed in claim 1 or 2., in which the magnetic field (10)applied across the bead (6) is given such a strength and/or durationthat the particles (9), during their orientation in the same directionas the magnetic field (10), affect the geometry of the bead (6).
 4. Amethod as claimed in claim 3, in which the magnetic field (10) isdirected so that the particles (9), during their orientation, affect thematerial of the bead (6) in such a manner that the bead assumes a shapetapering from a base (13) towards an apex (14).
 5. A method as claimedin any one of the preceding claims, in which the magnetic field (10)applied across the bead (6) is given such a strength and/or durationthat a concentration of particles (9) is provided in the surface layer(15) of the bead (6).
 6. A method as claimed in any one of the precedingclaims, in which said bead (6) is made by a dispensing process.
 7. Amethod as claimed in any one of claims 1-5, in which said bead (6) ismade by a screen-printing process.
 8. A method as claimed in any one ofthe preceding claims, in which the material (7) is arranged in the formof a bead (6) on a substrate (8) and arranged for adhesion thereto.
 9. Amethod as claimed in any one of the preceding claims, in which thematerial (7) is arranged in the form of a bead (6) on a substrate (8),the magnetic field (10) being directed so as to act perpendicular to andin a direction away from the surface (11) of the substrate (8), on whichsurface (11) the material (7) is arranged.
 10. A method as claimed inany one of the preceding claims, in which the magnetic field appliedacross the bead (6) has a flux density in the range 0.01-1 Tesla.
 11. Amethod as claimed in any one of the preceding claims, in which saidmaterial (7) is selected from the group consisting of silicone rubber,polyurethane and TPE.
 12. A method as claimed in claim 11, in which thestep of orienting the particles (9) is followed by the step of treatingthe material (7) by a curing process, whereby the material (7) assumesan elastic, non-viscous state while the particles (9) are fixed withmaintained orientation.
 13. A method as claimed in any one of thepreceding claims, in which the particles (9) are formed so as tocomprise a ferromagnetic material such as iron, nickel, cobalt or analloy containing one or more of said ferromagnetic materials.
 14. Amethod as claimed in any one of the preceding claims, in which theparticles (9) carried by the material (7) are formed with an outer layerof a material with substantial electrical conductivity.
 15. A method asclaimed in any one of the preceding claims, in which the particles (9)carried by the material are formed with an outer layer which forms anoxidation inhibitor for a ferro- and/or ferrimagnetic material arrangedinside the outer layer.
 16. A method for manufacturing anelectromagnetic shielding element (5), characterised by the steps ofarranging, by a dispensing process and along a curve corresponding tothe extension of the completed element (5), a bead (6) of a viscousmaterial (7), such a silicone rubber, and particles (9) carried thereinand having substantial electrical conductivity and ferro- and/orferrimagnetic properties on a substrate (8), orienting the particles (9)carried by the material (7) by applying a magnetic field (10) across thebead (6), the magnetic field (10) being directed so as to actperpendicular to the substrate (8) in a direction away from the surface(11) of the substrate (8), on which surface (11) said bead (6) isarranged, and treating the material (7) so as to assume an elastic,non-viscous state.
 17. A device for electromagnetic shielding,comprising an element (5) manufactured according to the method asclaimed in any one of claims 1-15.
 18. An element for electromagneticshielding, comprising an elastic material (7) carrying particles (9)with substantial electrical conductivity, characterised in that theparticles (9) are oriented in the material (7) and the element has ashape tapering from a base (13) towards an apex (14).
 19. An element asclaimed in claim 18, in which said particles (9) are oriented so that aconcentration of particles (9) is present in a surface layer (15) of thematerial (7).
 20. An element as claimed in claim 18 or 19, in which thematerial (7) consists of silicone rubber, polyurethane or TPE.
 21. Anelement as claimed in any one of claims 18-20, in which the particles(9) have ferro- and/or ferrimagnetic properties.
 22. An element asclaimed in claim 21, in which the particles (9) comprise nickel, iron,cobalt or an alloy containing one or more of these.
 23. An element asclaimed in any one of claims 18-22, in which the particles (9) have anouter oxidation-inhibiting layer with substantial electricalconductivity.
 24. An element as claimed in claim 23, in which theoxidation-inhibiting layer contains silver.
 25. An element as claimed inany one of claims 18-24, in which the elastic material (7) also carriesparticles with substantial electrical conductivity and without ferro-and/or ferrimagnetic properties.
 26. Use of an element (5) according toany one of claims 18-25 for electromagnetic shielding in a mobile phone.27. A mobile phone, comprising an element (5) for electromagneticshielding according to any one of claims 18-25.
 28. Use of an element(5) according to any one of claims 18-25 for electromagnetic shieldingat a base station.
 29. A base station for mobile telephony, comprisingan element according to any one of claims 18-25.